Two Magnetospheric Multiscale, or MMS, spacecraft comprising the mission’s upper stack are towed between Buildings 1 and 2 of the Astrotech payload processing facility in Titusville, Florida, near Kennedy Space Center. The two MMS spacecraft comprising the lower stack arrived at Astrotech on Oct. 29. The Magnetospheric Multiscale mission is a Solar Terrestrial Probes mission comprising four identically instrumented spacecraft that will use Earth’s magnetosphere as a laboratory to study the microphysics of three fundamental plasma processes: magnetic reconnection, energetic particle acceleration and turbulence. Launch aboard a United Launch Alliance Atlas V rocket from Space Launch Complex 41 on Cape Canaveral Air Force Station is targeted for March 12, 2015.